1. Field
This disclosure relates to methods of servicing a wellbore. More specifically, it relates to compositions and methods for drill stem testing.
2. Background
Natural resources such as gas, oil, and water residing in a subterranean formation or zone are usually recovered by drilling a wellbore down to a subterranean formation while circulating a drilling fluid via a drill string within the wellbore.
A drill stem test (DST) is commonly employed to determine the productive capacity, pressure, permeability, and/or extent of a hydrocarbon reservoir. DSTs are usually conducted utilizing a downhole shut-in tool that allows the well to be opened and closed at the bottom of the hole, for example, via a valve which may be actuated at the surface. Typically, during a DST, the zone of interest is isolated and reservoir fluids are allowed to flow through the drill string (e.g., pipe) for a time period. Samples of fluids produced from the DSTs are collected and analyzed to determine a variety of parameter which may be related to production such as the extent of resources (e.g., oil or gas) present in the formation. A DST may also be used to measure the flow rate of the fluids from the formation, the temperature and/or pressure associated with the formation, or combinations thereof. One challenge to conducting a DST in low temperature environments (e.g., offshore, permafrost, arctic drilling), is the potential for the formation of gas hydrates inside the drill string. Gas hydrates, in addition to potentially interfering with equipment operation (e.g., by plugging up a flow conduit) may pose a hazard to the operator. Thus there is an ongoing need for improved compositions and methodologies for use in DST.